A memory module comprises a circuit board (e.g. a printed circuit board, PCB) and a memory unit that is set onto the circuit board. The memory module is usually installed into the memory slot of a motherboard of a computing apparatus for data storage. For example, the memory module may be a dynamic random access memory (DRAM) module which is packaged as a single in-line memory module (SIMM), a double in-line memory module (DIMM) or the like. The connectors on either side are connected to each other in the SIMM, but this is not the case with the DIMM. Compared to the SIMM with a 32 bit bus, the DIMM with a 64 bit bus allows twice the data to pass through.
To ensure the efficiency and stability of the memory module, several kinds of detection devices (which may be configured inside or outside the memory module) are known to detect various kinds of parameters (e.g. temperature, transmission rate etc.). Also, various kinds of display units (e.g. LED displays) are added into the memory module to provide users with detected information. In addition to the memory unit and the display unit, a micro control unit (MCU) configured to control the display unit is generally added into the memory module. The MCUs of all memory modules that have respective bus addresses for identification by a central processing unit (CPU) installed into a motherboard may be electrically connected to the CPU through the same bus of the motherboard (e.g. a system management bus). The CPU may transmit instructions to the MCUs of the memory modules according to their bus addresses respectively so that each memory module can control its display unit by its MCU based on the corresponding instruction from the CPU.
When the CPU wants to instruct several MCUs to control the respective display units in the memory modules, it cannot transmit commands to the MCUs synchronously (i.e., at the same time) because the MCUs have different bus addresses. The display units cannot work synchronously either because of the time difference of transmitting the commands. In addition, since the CPU cannot transmit the commands to the MCUs at the same time, it will take more time to instruct all of the MCUs to control the display units, especially as the number of the memory modules increases. Accordingly, an urgent objective in the art is to overcome the limitation in that the CPU cannot synchronously instruct the MCUs and the MCUs cannot synchronously control the display units.